Invasive Plants Have Far-Reaching Impact on Vermont’s Ecology
The presence of invasive plants can have a major impact on the insects that are found in an area. Studies have shown that an increase in invasive plant density can often lead to a decrease in native insect density. Non-native plants are considered invasive when they have the ability to outcompete native plants for resources and become the dominant plant in an area. Because many insects have evolved specifically to feed on certain plants, the loss of the native plants can result in the loss of a necessary food source, causing the native insects to die or move to new locations. The loss of insect populations can have larger repercussions in an ecosystem; without them, birds are unable to find enough food to feed their young. For example, Carolina chickadees must live in areas with more than 70 percent native plants in order to find enough caterpillars to feed their chicks, so the presence of native plants and insects is crucial for their survival. Some invasive plants are extremely toxic to insects. The invasive black swallowwort is poisonous to monarch butterflies, which need to lay their eggs on its relative, the common milkweed. The butterflies may confuse black swallowwort for milkweed in places where the invasive has crowded out its cousin, leading to the demise of their larvae before they reach adulthood. Garlic mustard, a small herbaceous invasive commonly found throughout southern Vermont, is harmful to the mustard white butterfly for the same reason. Contact Elana at [email protected] with any questions about invasive plants or visit vtinvasives.org.